High tension circuit breakers



May 22, 1956 H, FORWALD 2,747,055

HIGH TENSION CIRCUIT BREAKERS Filed May 28, 1953 5 Sheets-Sheet l Frg/ /0 f/ /6 I2 I73 /7 f4 75 INVENTOR. flaakon Tom/aid May 22, 1956 H. FORWALD 2,747,055

HIGH TENSION CIRCUIT BREAKERS Filed May 28, 1955 s Sheets-Sheet 2 omey.

May 22, 1956 H. FORWALD HIGH TENSION CIRCUIT BREAKERS 3 Sheets-Sheet 3 Filed May 28, 1953 ln VP/7 for Haa kon Far/m /d Z) ##ome yr United States Patent HIGH TENSION CIRCUIT BREAKERS Haakon Forwald, Ludvika, Sweden, assignor to Allmiinna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, 2 Swedish corporation Application May 28, 1953, Serial No. 357342 Claims priority, application Sweden May 31, 1952 4 Claims. (Cl. 200-448) It has previously been proposed to arrange the compressed air container of an air blast circuit breaker on the top of a pillar insulator and to arrange the breaking contacts inside the container and to dimension the container so that it contains an air quantity that is sufficient for at least one interruption. to this container is then performed through an insulating pipe line from the magazine on the ground, or from a delivery line for compressed air. This arrangement has the important advantage that the compressed air necessary for the extinction is at rest in the immediate vicinity of the breaking gap which has proved to be very advantageous for an effective extinguishing of the interruption are. A further advantage is that it is not necessary to be concerned with any pressure drop for the extinguishing air which, on the contrary, must be taken into account if an air blast valve is inserted between the breaking gap and the air blast container. This is especially the case if the air blast valve is arranged at the base of the circuit breaker, because in that case a pressure drop is to be taken into account in a long pipe line from the blast valve to the breaking gap.

The present invention concerns a high tension circuit breaker of the above mentioned kind with a plurality of compressed air containers, containing breaking gaps and with or without equalization and extinguishing resistances, which containers are arranged on a plurality of separate pillar insulators. The invention is chiefly characterized thereby that the delivery of the extinguishing air to the different air containers is performed to at least one of the containers and from this container to the other containers through pipe lines which connect them and which at the same time may serve as electrical connections between the breaking gaps in the containers.

The invention effects a considerable saving of insulating compressed air pipe lines by the arrangement wherein the compressed air is delivered from one container to the others. This saving is especially pronounced if the transmission of compressed air is performed through tubular electric connections between the breaking gaps. There is also a considerable saving in the delivery line to the containers, because the re-filling of the containers between the different extinguishing occasions can be performed during a comparatively long time so that the delivery line may have a small cross sectional area.

In spite of the fact that preferably only one insulated delivery line to the container is used, it is, however, also possible to provide the air through a plurality of pipe lines and to more than one of the containers.

On the accompanying drawings Fig. 1 shows a form of the invention. Fig. 2 shows schematically one of the compressed air containers with insulating bushings, contacts and operating mechanism, whereas Fig. 3 shows an operating mechanism in detail. In Fig. 1, the numerals 1, 2 and 3 designate three pillar insulators which rest on base frames 4, 5 and 6 and carry compressed air containers 7, 8 and 9, to which are attached, on each, two insulating bushings 10, 11, 12, 13, and 14, re-

The delivery of compressed air spectively. The breaking gaps in the different air containers are connected in series to each other by means of tubular connections 16 and 17 which also serve to transmit compressed air from the container 3 to the containers 7 and 9 respectively. The current to the circuit breaker is delivered through the conductor 18 and is taken out from the breaker through the conductor 19.

36, 3i, 32, 33, 34, and designate operating mechanisms and blast valves for the breaking gaps in the containers. These different operating mechanisms and blast valves are operated by compressed air which is delivered through the tubular insulators 36, 3'7, and 38. This operating air is delivered to these insulators through an electro-magnetical operating valve arranged in the base frame 5.

Fig. 2 shows in detail a compressed air container 8 with its insulating bushings 12 and 13. 16 and 17 are the tubular conductors to the stationary contacts 39 and it) or the breaking gap. In these contacts there are openings 41 and 42 through which air escapes from the container 8 to the other containers, whereas air is delivered to the container 8 through the pipe line B. in Fig. l, the pillar insulators 1, 2, and 3 are only schematically indicated. In reality they are built up from screen insulating elements 43 which are joined with each other by means of metal armatures 43:! as indicated in Fig. 2.

Fig. 3 shows the operating mechanism for a breaking gap. In this figure, 44 designates the wall of a compressed air container in which a mechanism housing 45 is inserted. in this housing there is an opening 46 in the upper part, through which the movable contact 47 of the circuit breaker projects into contact with the stationary contact 40 which is attached to one of the insulating bushings in the compressed air containers. The movable contact 47 is connected with a piston 49 which moves in a cylinder 50 which is provided with a collar 51 with tightening gasket 52 which engages tightly against the edges of the annular formed outlet opening 53 in the lower part of the housing 45. In the lower space of this housing there is a piston 56 which by means of the rod 57 is connected with the piston 49. From the intermediary wall 58 in the housing a pipe 59 projects up into the cylinder 50 and is there terminated by means of a collar 60 which on the upper side is provided with a tightening ring 61. The piston 56 is provided with a non-return valve 62. 63 is the delivery line for operating air to the mechanism. This line is branched in the first place to a case 64 containing a membrane, and in the second place through a channel 65 to the space in the housing 55 below the piston 54, and, in the third place, over a throttle and a non-return valve 66, 67 to the space in the housing 55 above the piston 54. The space below the piston 56 is, by a channel 68, in communication with a three-way-valve 69.

The arrangement acts in the following way:

When compressed air is delivered through pipe line 63 which corresponds to the pipe lines 36, 37, and 33 in Fig. l, compressed air is delivered to the membrane case 64 so that the membrane in it acts upon the valve disc 76 in the valve 69 so that the space below the piston 56 is in communication with the free air at the same time as the delivery line '71 for compressed air from the container is closed. At the same time as this takes place compressed air is delivered to the space below the piston 54 so that it is raised and moves the cylinder 56 upwards until the piston 54 reaches the tightening ring 72. As the outlet opening 53 is thus opened, the space in the housing 45 is evacuated so that the movable contact 47 is moved downwards by the air pressure in the container until the collar 73 reaches the upper edge of the cylinder 50. As the contacts 40 and 47 then are separated, an arc is formed between them and the compressed air in the container streams in between the contacts and through the channels 74 of the contact 47 to the space in the housing 45 and from there escapes through the outlet opening 53. In the same degree as air flows in through the throttle valve 66 to the space above the piston 54, this is moved downwards under co-action of the spring 75 until the outlet opening 53 has been closed again. At this motion the movable contact 47 follows downwards until the piston 49 is forced against the tightening ring 61 which occurs a short time before the opening 53 is closed. Thereby the distance between the contacts 47 and 49 is increased to a degree preventing a flash over. When the breaker shall be closed again, the pipe line 63 is evacuated. The piston 54- will then rest in its position because the air is evacuated from both sides thereof. At the evacuation the valve disc 70 is moved to the right so that compressed air from the container through the line 71 and the line as is delivered to the space below the piston 56 so that it is moved upwards simultaneously closing the non-return valve 62. When the piston 56 moves upwards, the movable contact 47, by means of the rod 57, is brought into engagement with the stationary contact 40.

I claim as my invention:

1. An air blast circuit breaker having a plurality of series-connected breaking gaps and comprising a plurality of compressed air containers arranged in spaced relation to each other, contacts for said gaps arranged within said containers, a pillar insulator supporting each individual,

each container having a volume so large that the com- 30 pressed air contained therein is suflicient for at least one extinguishing of the are between the breaking contacts therein, pipe lines extending directly between the spaced containers and providing for the passage of air from one of said containers to another, and at least one pipe line for the delivery of compressed air to said containers.

2. An air blast circuit breaker having a plurality of series-connected breaker gaps and comprising contacts for said breaker gaps, a plurality of compressed air containers spacer from each other each enclosing a plurality of said contacts and each having a volume sufiicient to hold enough compressed air for at least one extinguishing of the are between the enclosed breaking contacts, an insulated pipe line for delivering compressed air directly to at least one of said containers, a pipe line whereby at least one other of said containers is supplied with compressed air from the container that receives air from the said insulated pipe line, and a plurality of insulating pillars one supporting each of said containers.

3. A circuit breaker according to claim 1, in which the pipe lines extending between the containers are made of metal and simultaneously serve for electrically connecting the members in one container in series with those in an adjacent container.

4. A circuit breaker according to claim 1, in which the contacts of the breaking gaps in the containers are electrically connected in series with each other by the said pipe lines extending between said containers.

References Cited in the file of this patent UNITED STATES PATENTS 2,153,400 Trencham Apr. 4, 1939 2,336,316 Thommen Dec. 7, 1943 2,453,555 Thommen Nov. 9, 1948 

